ucl/_docs/mod/csv.md

# CSV Module

Functions for operating over CSV data.

### each-record

```
csv:each-record FILE BLOCK
```

Opens the CSV file at FILE and calls BLOCK on each record. It is expected that this
CSV file has a header which appears as the first row. This command will read and
index the header, then start calling BLOCK from the row directly below the header.

BLOCK is called with the arguments _|row header|_ where:

- _row_ contains the fields of the current row as a list.
- _header_ contains a hash mapping a header name to a field index.

The return value will be nil.

```
csv:each-record "winds.csv" { |row hdr|
  set name $row.($hdr.name)
  set bearing $row.($hdr.bearing)
  
  echo "Wind $name has bearing $bearing"
}
```

### to-csv

```
csv:to-csv CONT [-header HEADER] [-stdout]
```

Produces a CSV using the items of CONT and writes it as a string. CONT must be a list of iterator of hashable
elements.

If HEADER is defined, it must be a list of strings identifying the name and order of the hash keys to read
from each hashable item of CONT. If HEADER is not defined, then the keys of the first consumed hashable item will be
used, with the keys sorted in alphabetical order.

If `-stdout` is set, the CSV will be written to standard out and `to-csv` will return the empty string.